Liquation of copper



Feb. 2, 1932; J. o. BETTERTON 1,

'LIQUATION OF COPPER Filed May 25, 1928 BLAST FURNACE L EAD BULL/0NREMOVED HEATED TO 7857'.

COOLED T0 550V"? APPROXIMATELY 25% BECOMES FROZEN LIQUID PORT/0N TflPPED0 501.10 PORT/0N REMELTED. A5 REF/NED Pb L CONTAINS Cu /N c EUTECT/CPROPORTION To MELT/N6 P0 NT 0/ LE/ID. Dfi055 FORMED.

LIQUID CON TA/NS 0Ross REMOVED L REMAINING Cu.

RETURNED T0 FURNACE FOR cu RECOVERY ADDED TO MORE BULL/0N FOR FURTHERTREATMENT.

INVENTOR.

f 0% BY M0 7:1.M'

ATTORNEY Patented Feb. 2, 1932 UNITED STATES PATENT VOFFICE mssn oA'rMANBEr'rEaroN, or OMAHA, NEBRASKA, ASSIGNOR :ro AMERICAN smmrrme & nnrmmecomrAmr, or NEW YORK, N. Y., A coRroRA'rIoN or NEW JERSEY LIQUATIoN 'orcorr in Application filed Kay 23, 1928. Serial No. 279,880.

This invention relates to lead refining and more particularly to a newand improved process of removing copper from lead bul-' lion.

In accordance with the present invention, copper and various otherimpurities are removed from lead bullion by selective freezing wherebythe liquid portion comprises lead of a suflicient degree of purity forcertain commercial purposes. Skimming is eliminated by tapping themolten metal after the Impurities have been selectively frozen out andallowing the metal to run into suitable containers for further use. Theimpuritiesare then remelted and separately recovered.

The invention also consists in certain new and original features ofconstruction and combinations of parts hereinafter set forth andclaimed.

' Although the novel features which are believed to be characteristic ofthis invention will be particularly pointed out in the claims appendedhereto, the invention itself, as to its objects and advantages, the modeof its operation and the manner of its organization may be betterunderstood by referring to the following description takenin connectionwith the accompanying drawingforming a part thereof, in which The figureis a flow sheet representing one method of practicing the invention.

In the following description and in the claims parts will be identifiedby specific 3 names for convenience, but they are intended a smallportion of the lead to solidify. line to thevheat radiation at thesurface and sides of the bath these portions will become solid I lead,and may be eliminated from the remaining liquid portion down to a degreecorrespondmg substantially to their eutectic with lead. In the case ofcopper substantially .065% will remain, the balance being con-,.

tained in the frozen portion. This percentage is sufficiently low toenable the lead to be employed for commercial purposes without furtherrefining. Thev liquid portion, which comprises most of the lead, maythen be tapped oif and cast into bars for the market.

The solid portion containing the greater percentage of copper is thenremelted and again cooled substantially to the freezing point of lead.The solid portion will contain a large proportion of the remainingcopper and may be returned to the furnace for further refining, or maybe allowed to remain in the kettle until a suflicient amountaccumulates, when it may be drossed in the usual manner, and th'edrossreturned to the furnace. The liquid portion is added to the bullionwhich is taken from the smelting furnace and is further treated forcopper removal in accordance with the foregoing steps.

bullion containing 255% copper was heated Considering a specificexample, a mass of to a temperature of 785 degrees F. and then cooled toa temperature of substantially 580 degrees F. At this temperature about25% of the metal was frozen and contained the major portion of thevarious impurities. The remaining molten-bullion contained substantially065% copper, which is the eutectic of copper and lead. This metal wastapped and marketed. The frozen portion, or crust, was then remelted andafterfurther cooling, during which metallic dross was formed thereon,was tapped and added to further quantities of blast furnace bul lion andagain treated for copper removal. The metallic dross, which contained31.73% of the copper originally present, was then returned to the blastfurnace and treated for copper removal. This dross forms the outlet ofcopper for the entire system, whereas the tapped metal, containing 065%of copper, is the outlet of lead. After the process has been placed inoperation, it automatically stabilizes with an outlet of refined lead atthe first tap and an outlet of copper at the final dross. Obviously, thepercentages given above may vary in accordance with the particularbullion under treatment. Certain figures have been set forth by way ofillustration, only.

Referring to the mechanical features of the process, the bullion fromthe blast furnacc is collected in a kettle provided, preferably with atap at .the bottom thereof. When filled, the kettle is allowed to coolto a point approximately at the melting point of lead and is maintainedin this condition until some 25% of the original metal has becomefrozen. The remaining 75% of the original bullion is tapped as a bullioncontaining approximately .06 5%- copper and used for moulding and otherpurposes where it will require no further special treatment for copperremoval.

The frozen portion comprising approximately 25% of the original bullionis remelted and is pumped to another receiving kettle. It is then meltedand treated for the removal of a copper dross which is the outlet forcopper of the entire system. The remaining liquid is then pumped toanother receiving kettle, is further cooled to reduce the copper contentto a point similar to that of the original bullion and is then treatedwith further quantities of bullion from the blast furnace. The processstabilizes with an outlet for copper in the dresses at one point and anoutlet for bullion suitable refining operations at another point. Thequantity of material treated may be reduced by employing mixing machinesfor drying the various, dresses and reducing the volume thereof beforereturning the same to the furnace. l

The invention has been specifically described for the sake of clearnessas applied to lead bullion. It is. however. applicable to the refiningof other metals. such as antimonial lead. This la'tter metal has beenrefined by the above mentioned proc ess to an :n'erage of .087r copper.which was then further diluted with refined lead and used as batteryplate alloy.

In carrying out the process it not essential to freeze out anyparticular proportion of lead after the mass of bullion has for reachedthe freezing point of leadf In operating on a commercial scale it wasfound preferable, however, to allow approximately 25% of the material tobecome frozen since the heat radiation from the surface of the bathrendered the maintenance of an even temperature extremely difficult. Thelead was therefore allowed to freeze on the surface and around the sidesof the kettle in order to permit the central portion of the bath toreach the desired temperature.

Although certain novel features of the invention have been shown anddescribed and are pointed out in the annexed claims, it will beunderstood that various omissions, substitutions and changes in theseveral steps of the process and in its operation may be made by thoseskilled in the art without departing from the spirit of the invention.

lVhat is claimed is:

1. The process of refining lead bullion for the removal of copper downto appoint corresponding to the eutectic of copper and lead whichcomprisesheating said bullion to a temperature substantially above themelting point of'lead and cooling the top and sides of the masssufiiciently below the eutectic temperature to cause a substantialportion of the bullion at the top of the sides to solidify and to bringthe temperature of the interior to substantially the eutectictemperature, whereby the copper in the liquid portion is reduced to theeutectic'proportion and then removing the liquid from below the solid.portion, re-melting said solid portion and said bullion to atemperature of approxim ately 7 85 F., whereby the entire mass becomesliquid and over-cooling the bullion at the surface and sides to a.temperature of approximately 580 F. whereby the interior is cooled tosubstantially the'eutectictemperature of lead and copper andapproximately 25% of the metal becomes frozen, removing the liquidportion which contains copper in substantially the eutectic proportion,re-melting. the solid portion and cooling the same to the melting pointof lead to produce a dross containing substantial quantities of copper,removing the dress and returning the liquid for re-treatment inaccordance with the above pro Jess. y i

3. The process of refining lead bullion for the removal of copper totheeutecticpropon tion which comprises heating said bullion to atemperature above the melting point thereof and allowing the same toslowly cool from the surface and sides to a temperature at whichapproximately 25% thereof becomes frozen, whereby the liquid portioncontains a percentage of copper corresponding to the eutectic, removingthe liquid from below the solid portion remelting and further decreasingthe copper content of said solid portion by progressively cooling toform a copper dross, removing the dross and returning the liquid fortreatment with further quantities of bullion in accordance with theabove process.

In testimony whereof I have hereunto set my hand.

JESSE OATMAN BETTERTON.

